Análise de viabilidade da utilização de resíduos de pinus para construção de blocos de bio-concreto para alvenaria de vedação

Abstract

This research assessed the use of Pinus wood sawdust as a bio-aggregate in non-structural bio-concrete blocks with the aim of reducing sand consumption. Three treatment methods were compared to remove biomass extractives and mitigate incompatibilities with the cement matrix. The methods included immersion in a sodium hydroxide (NaOH) solution, wetting and drying cycles, and immersion in water heated to 80o C. Each method was applied to two substitution percentages of sand mass with sawdust, resulting in seven distinct mixes, including the reference mix without sawdust. The blocks were produced with a constant water- to-cement ratio (w/c) of 0.6, resulting in final proportions of 1:4:0.6 for the reference mix, 1:3.92:0.08:0.6 and 1:3.98:0.02:0.6 for the mixes with 2% and 0.5% substitution, respectively. The bio-blocks were evaluated for compressive strength, water absorption, and thermal conductivity, meeting the requirements of the NBR 6136 standard (ABNT, 2016). The bio- blocks with 0.5% substitution for all three treatments showed compliance in strength, with the NaOH-treated bio-blocks exhibiting an average strength superior to the reference mix. All mixes met the standardized limits for water absorption, and the bio-blocks demonstrated improved thermal insulation capability with increasing substitution percentage of sand with the bio-aggregate.